Resolved Schmidt-Kennicutt relation in a binary hyperluminous infrared galaxy at $z=2.41$

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Main Authors: Gómez, Jonathan S., Messias, Hugo, Nagar, Neil M., Orellana-González, Gustavo, Ivison, R. J., van der Werf, Paul
Format: Preprint
Published: 2025
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author Gómez, Jonathan S.
Messias, Hugo
Nagar, Neil M.
Orellana-González, Gustavo
Ivison, R. J.
van der Werf, Paul
author_facet Gómez, Jonathan S.
Messias, Hugo
Nagar, Neil M.
Orellana-González, Gustavo
Ivison, R. J.
van der Werf, Paul
contents Hyperluminous infrared galaxies (HyLIRGs; SFRs up to about 1000 Msun yr-1), though rare, provide key constraints on galaxy evolution. H-ATLAS J084933.4+021443, a z = 2.41 binary HyLIRG (galaxies W and T) with two additional luminous companions (C and M), offers an ideal laboratory for studying star formation during "cosmic noon". We use ALMA to obtain resolved imaging and kinematics of CO J:7-6, [C I] 2-1, H2O, and rest-frame 340-1160 GHz continuum emission in all four galaxies. Each system is spatially resolved within ~0.3 arcsec (2.5 kpc) apertures. Gas kinematics in W and T are rotation-dominated, with galaxy T showing emission extended along its kinematic minor axis due to lensing magnification. Spatially resolved SEDs indicate that W is well fitted by single-temperature greybody dust despite hosting a luminous AGN, while T requires an additional hot-dust component and extra millimetre emission. We confirm [C I] J:2-1 as a tracer of warm/dense molecular gas in these extreme systems, though its luminosity ratio with CO J:7-6 rises sub-linearly. We derive resolved (2.5 kpc-scale) Schmidt-Kennicutt (SK) relations for W and T using both cold and warm/dense gas, finding depletion times of about 50-100 Myr (W) and about 100-500 Myr (T). Both galaxies follow a steep SK relation with power-law index n ~ 1.7, significantly above the n ~ 1 observed in normal star-forming galaxies.
format Preprint
id arxiv_https___arxiv_org_abs_2511_06537
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Resolved Schmidt-Kennicutt relation in a binary hyperluminous infrared galaxy at $z=2.41$
Gómez, Jonathan S.
Messias, Hugo
Nagar, Neil M.
Orellana-González, Gustavo
Ivison, R. J.
van der Werf, Paul
Astrophysics of Galaxies
Hyperluminous infrared galaxies (HyLIRGs; SFRs up to about 1000 Msun yr-1), though rare, provide key constraints on galaxy evolution. H-ATLAS J084933.4+021443, a z = 2.41 binary HyLIRG (galaxies W and T) with two additional luminous companions (C and M), offers an ideal laboratory for studying star formation during "cosmic noon". We use ALMA to obtain resolved imaging and kinematics of CO J:7-6, [C I] 2-1, H2O, and rest-frame 340-1160 GHz continuum emission in all four galaxies. Each system is spatially resolved within ~0.3 arcsec (2.5 kpc) apertures. Gas kinematics in W and T are rotation-dominated, with galaxy T showing emission extended along its kinematic minor axis due to lensing magnification. Spatially resolved SEDs indicate that W is well fitted by single-temperature greybody dust despite hosting a luminous AGN, while T requires an additional hot-dust component and extra millimetre emission. We confirm [C I] J:2-1 as a tracer of warm/dense molecular gas in these extreme systems, though its luminosity ratio with CO J:7-6 rises sub-linearly. We derive resolved (2.5 kpc-scale) Schmidt-Kennicutt (SK) relations for W and T using both cold and warm/dense gas, finding depletion times of about 50-100 Myr (W) and about 100-500 Myr (T). Both galaxies follow a steep SK relation with power-law index n ~ 1.7, significantly above the n ~ 1 observed in normal star-forming galaxies.
title Resolved Schmidt-Kennicutt relation in a binary hyperluminous infrared galaxy at $z=2.41$
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2511.06537